Officials say an engine fix is near at hand for the F-35, following a June fire. (Matthew Short / Lockheed Martin)

F-35 Joint Strike Fighter

WASHINGTON — Engine manufacturer Pratt & Whitney is close to performing tests on a potential design change for its F135 engine following a June incident that led to the devastation of an F-35 Joint Strike Fighter.

Inspectors are still investigating the root cause of the incident to determine if it was a manufacturing or design flaw, but in the meantime the company has begun design on a potential solution.

Speaking to Defense News on Aug. 25, Gen. Mark Welsh, the Air Force chief of staff, expressed confidence that the issue was close to being resolved.

“We know how to prevent it from occurring again by making a redesign in the engine. And, that is what the engine company is working on.

“I think they are probably pretty close to that, and then they will have to make changes to the manufacturing process to ensure that that is good for the future.”

Just what that fix will be remains unclear.

“We have a potential fix that we believe will eliminate the problem, and we will conduct engine and rig tests next month to verify that with the Services and the Joint Program Office,” Pratt spokesman Matthew Bates said in an email. However, Bates declined to reveal further details.

A spokesman for the F-35 Joint Program Office confirmed the root cause analysis into the cause of the fire is still ongoing.

“We are very concerned, because it is a developmental program still, and we do not want it to ever happen again,” Welsh said.

While the investigation moves apace, the F-35 fleet remains under flight restrictions that some observers say could have an impact on planned initial operational capability (IOC) dates for the three US services acquiring the aircraft.

The Marines plan to go to IOC next summer, followed by the Air Force in 2016 and the Navy by 2019. As the first service up, the Marines are the most likely to be affected by training and testing delays, but Welsh said the Air Force is also keeping an eye on the situation.

“They still do limit our ability to fly test patterns, test sorties and to accomplish all the test points we need,” Welsh said “So it is still having this dampening effect on getting through the test profiles, and we are just going to have to adjust to that.”

Asked whether the Air Force had set a target date for when the restrictions could put IOC in peril, Welsh said that has not been decided.

“We have not established a firm date for that, and I think until this continues a little bit longer, I do not think we need to establish a firm date,” he said.

The Air Force has a little bit of leeway built into its IOC date. While the target IOC date is August of 2016, the service has a deadline of December 2016. In other words, IOC could happen anytime in that period and the Pentagon can still declare it happened on time.

The service considers the threshold for IOC to involve a full operational squadron of 12-24 aircraft with trained pilots.

Welsh expects that “by the end of the year we are going to be out of most of the restrictions that are slowing us down in the test process now,” and noted that restrictions on the test fleet have been loosened since the initial order. ■